The functions of this core facility are to provide an efficient, economical and effective use of animals for the performance of cancer- related studies. A significant emphasis is placed on the use of immune- deficient rodents. Major services provided by the Animal Core Facility include: coordination of animal purchase requests; inoculation of tumor cells into animals; in vivo propagation of tumor cell lines in animals; measurement of tumors; administration of carcinogens, drugs and hormonal agents; collection of tumors, organs, and sera. A service for the production of rabbit polyclonal antisera is also provided. Small transgenic and C3H OUJ mouse breeding colonies are maintained. Two additional rooms are also maintained to N.I.H. Biosafety Level 2 standards for investigators using retroviral vectors and chemical carcinogens. The facility is located within Georgetown University Medical School's Research Resources Facility (RRF). The RRF is a centralized, AAALAC accredited, USDA registered, animal facility and has an approved letter of assurance on file at the N.I.H. All cell lines for inoculation require evidence of current Murine Antibody Production test status. The general environment and animal health is monitored by the use of sentinel mice are maintained in each animal room. All immune-deficient rodents are maintained within a Specific Pathogen free environment. The services of this facility are critical to the effective and economical use of animals by Lombardi Cancer Center investigators. In FY 91-92, these services were used in support of 16 peer-reviewed projects in 7 Cancer Center Programs. At the time of the previous CCSG application, this facility had the capacity to maintain up to 600 athymic nude mice at any one time. Continuing increase in demand has required a 50% expansion in space required to maintain immune-deficient rodents. We anticipate a further 50% increase in usage over the next 5 year period. A substantial proportion of this increase will occur within the first 24 months.